Researchers at MIT have developed a miniaturized cannula that employs a needle as thin as a human hair to directly deliver drugs to highly specific brain regions, even as small as one cubic millimeter. This direct dosing approach could allow doctors to target specific brain circuits, potentially helping to reduce side-effects in the rest of the brain and increase treatment efficacy.
Pharmacological treatments for brain disorders can often have significant side-effects as the drug spreads throughout the entire brain. “Even if scientists and clinicians can identify a therapeutic molecule to treat neural disorders, there remains the formidable problem of how to deliver the therapy to the right cells — those most affected in the disorder,” says Ann Graybiel, a researcher involved in the study. “Because the brain is so structurally complex, new accurate ways to deliver drugs or related therapeutic agents locally are urgently needed.”
The new device consists of a series of connected tubes with diameters of approximately 30 micrometers and lengths of up to 10 centimeters. The researchers used microfabrication techniques to connect and arrange the microtubes within a stainless-steel needle that has a diameter of 150 microns, which is approximately the thickness of a human hair.
The team was able to place the cannula in specific brain regions in rats and use it to exert precise control over the dose of a delivered drug, as well as the exact brain region targeted for treatment. By connecting the device to a small remote-controlled pump that is implantable under the skin, the researchers could precisely control the dose delivered through the needle.
In a test in rats, the team was able to deliver a drug to a targeted brain region, and were able to affect their motor function. When the researchers used the device to flush the brain region with saline, the motor effects diminished, showing that the treatment could be halted at will.
“We believe this tiny microfabricated device could have tremendous impact in understanding brain diseases, as well as providing new ways of delivering biopharmaceuticals and performing biosensing in the brain,” said Robert Langer, another researcher involved in the study.